1. Field of Invention
The present invention relates to a display device. More particularly, the invention relates to a display device that is basically tubular and has a display panel disposed along the outside circumference.
2. Description of Related Art
Tubular display devices that are worn on the wrist, for example, are known from the literature. The frame of the display device may have a thin display panel such as an electrophoretic display panel disposed along the outside circumference surface of the frame as taught in Japanese Unexamined Patent Appl. Pub. JP-A-2005-250442.
The display panel (display unit) of the display device taught in JP-A-2005-250442 is connected to a flexible printed circuit that is populated with the electronic components for driving the display device by a connector unit. The display panel and flexible printed circuit are folded together at the connector unit. The flexible printed circuit is disposed directly on the outside surface of the bobbin-shaped frame, and the display panel is disposed above the outside of the flexible printed circuit with a gap therebetween so that the flexible printed circuit is between the display panel and the frame.
If the electrophoretic display panel or other thin display panel is distorted, however, the distortion can degrade the image quality. It is therefore necessary in a display device that has a thin display panel disposed around the outside surface to install the display panel in a stable manner without applying unnecessary force.
In the display device taught in JP-A-2005-250442 the display panel must be rendered so that it is stable and substantially annular even though the display panel is floating above the flexible printed circuit. This can be done, for example, by holding the opposite edges of the display panel between a pair of rails disposed around the entire circumference of the frame. Because the restoring force of the display panel bent into a ring is suppressed by the rails disposed around the circumference of the frame, the display panel is easily distorted and image quality may be degraded.